1. Field of the Invention
The present invention relates to a computer system which automatically controls the on/off status of the power thereof and the start/stop of its operating system, by constantly monitoring the operational status of terminals.
2. Description of the Prior Art
In recent years, together with the development of the use of computer systems, the mode of using such computer systems has shifted from that concentrating on batch job processing to that concentrating on interactive processing using terminals, as exemplified by the TSS (Time-Sharing System). Especially in application fields in which computers are used for experimenting with and controlling instruments or the like (laboratory automation field), an experimenter will often conduct experiments and operate controls while conversing with a computer using terminals connected to the computer. In the field of laboratory automation (abbreviated hereinafter to "LA"), moreover, it is desirable that the researcher or experimenter be able to use the computer system as soon as an idea for an experiment occurs.
In order to satisfy that desire, it is necessary that the computer be capable of operating for 24 hour without interruption.
Usually, in LA using a computer system, a large computer and a minicomputer are hierachically connected so that large-scale data analysis is assigned to the larger computer, whereas the operation control and data gathering of experiment equipment are assigned to the smaller computer. Together with the improvement in processing capacity of minicomputers moreover, a method has been adopted in which a single minicomputer is shared by several experiment rooms and users, and is installed in a place remote from the experiment rooms. Of course all the operations in LA from the control of the experiment equipment to the data analysis may be performed by a large computer alone, without using a minicomputer.
As has been described above, it is desirable that an experimenter can promptly use a computer, even if it is midnight or a holiday, if he wants to. For this purpose, continuous 24-hour service is an essential condition for a computer system. When batch job processing and interactive processing such as TSS are combined, as in a large computer system, the continuous 24-hour service increases the utilization of the computer to a significant degree. However, if a computer assigned to experimental control alone is subjected to continuous 24-hour service, it is in operation even when it is not being used for experimental control. This reduces the utilization of the computer, and also wastes power.
If the computer operates only when it is required for controlling experiment equipment, on the other hand, the following problems arise: (i) an operator must be assigned to administer the operation of the system for each of several minicomputers and (ii) the experimenter must go to the remote place, in the absence of the operator, to start the supply of power to the computer system and initialize the system, or turn off the power supply and the system.
As a result of the increase in the necessity for continuous 24-hour service of computer systems, an automatic power on/off system has been proposed as one of the supports of an unsupervised computer system, in which the operation of the computer system is started or terminated at a predetermined time. However, this system is time-dependent, not user-dependent, so that the problem remains that the user is still inconvenienced.